I have a table car that looks like this:
| mileage | carid |
------------------
| 30 | 1 |
| 50 | 1 |
| 100 | 1 |
| 0 | 2 |
| 70 | 2 |
I would like to get the average difference for each car. So for example for car 1 I would like to get ((50-30)+(100-50))/2 = 35. So I created the following query
SELECT AVG(diff),carid FROM (
SELECT (mileage-
(SELECT Max(mileage) FROM car Where mileage<mileage AND carid=carid GROUP BY carid))
AS diff,carid
FROM car GROUP BY carid)
But this doesn't work as I'm not able to use current row for the other column. And I'm quite clueless on how to actually solve this in a different way.
So how would I be able to obtain the value of the next row somehow?
The average difference is the maximum minus he minimum divided by one less than the count (you can do the arithmetic to convince yourself this is true).
Hence:
select carid,
( (max(mileage) - min(mileage)) / nullif(count(*) - 1, 0)) as avg_diff
from cars
group by carid;
Related
I have a table that has the following schema:
ID | FirstName | Surname | TransmissionID | CaptureDateTime
1 | Billy | Goat | ABCDEF | 2018-09-20 13:45:01.098
2 | Jonny | Cash | ABCDEF | 2018-09-20 13:45.01.108
3 | Sally | Sue | ABCDEF | 2018-09-20 13:45:01.298
4 | Jermaine | Cole | PQRSTU | 2018-09-20 13:45:01.398
5 | Mike | Smith | PQRSTU | 2018-09-20 13:45:01.498
There are well over 70,000 records and they store logs of transmissions to a web-service. What I'd like to know is how would I go about writing a script that would select the distinct TransmissionID values and also show the timespan between the earliest CaptureDateTime record and the latest record? Essentially I'd like to see what the rate of records the web-service is reading & writing.
Is it even possible to do so in a single SELECT statement or should I just create a stored procedure or report in code? I don't know where to start aside from SELECT DISTINCT TransmissionID for this sort of query.
Here's what I have so far (I'm stuck on the time calculation)
SELECT DISTINCT [TransmissionID],
COUNT(*) as 'Number of records'
FROM [log_table]
GROUP BY [TransmissionID]
HAVING COUNT(*) > 1
Not sure how to get the difference between the first and last record with the same TransmissionID I would like to get a result set like:
TransmissionID | TimeToCompletion | Number of records |
ABCDEF | 2.001 | 5000 |
Simply GROUP BY and use MIN / MAX function to find min/max date in each group and subtract them:
SELECT
TransmissionID,
COUNT(*),
DATEDIFF(second, MIN(CaptureDateTime), MAX(CaptureDateTime))
FROM yourdata
GROUP BY TransmissionID
HAVING COUNT(*) > 1
Use min and max to calculate timespan
SELECT [TransmissionID],
COUNT(*) as 'Number of records',datediff(s,min(CaptureDateTime),max(CaptureDateTime)) as timespan
FROM [log_table]
GROUP BY [TransmissionID]
HAVING COUNT(*) > 1
A method that returns the average time for all transmissionids, even those with only 1 record:
SELECT TransmissionID,
COUNT(*),
DATEDIFF(second, MIN(CaptureDateTime), MAX(CaptureDateTime)) * 1.0 / NULLIF(COUNT(*) - 1, 0)
FROM yourdata
GROUP BY TransmissionID;
Note that you may not actually want the maximum of the capture date for a given transmissionId. You might want the overall maximum in the table -- so you can consider the final period after the most recent record.
If so, this looks like:
SELECT TransmissionID,
COUNT(*),
DATEDIFF(second,
MIN(CaptureDateTime),
MAX(MAX(CaptureDateTime)) OVER ()
) * 1.0 / COUNT(*)
FROM yourdata
GROUP BY TransmissionID;
I have a card game analyzation program that stores the results in an SQLite database with integer columns for the following values: round, table, game, pair, and score.
The schema of the "score" table is:
CREATE TABLE score(
round INTEGER,
table_number INTEGER,
game INTEGER,
pair_or_player INTEGER,
score INTEGER
);
E. g. a simple case for only two pairs and one round with two games each, where 21 points can be reached looks like this:
+-------+--------------+------+----------------+-------+
| round | table_number | game | pair_or_player | score |
+-------+--------------+------+----------------+-------+
| 1 | 1 | 1 | 1 | 8 |
| 1 | 1 | 1 | 2 | 21 |
| 1 | 1 | 2 | 1 | 21 |
| 1 | 1 | 2 | 2 | 14 |
+-------+--------------+------+----------------+-------+
A simple SELECT round, table_number, game, pair_or_player, score FROM score outputs:
1|1|1|1|8
1|1|1|2|21
1|1|2|1|21
1|1|2|2|14
What I need is an additional column with 21 minus the score of the opponent of the same game (identified by the same round, table_number and game, and a different pair_or_player), the result of the respective query would be:
1|1|1|1|8 |0
1|1|1|2|21|13
1|1|2|1|21|7
1|1|2|2|14|0
How can this be done?
You need to inner join the table with itself.
(I'm not entirely sure what you mean by pair, but let's assume there's an ID which identifies each match, a match being composed of two records, one for the winner, one for the loser):
SELECT winners.pair, winners.score, losers.pair, losers.score
FROM (SELECT pair, score FROM score WHERE score = 21) as winners
INNER JOIN (SELECT pair, score FROM score WHERE score < 21) as losers
ON winners.match_id = losers.match_id;
I found it myself.
SELECT
a.round,
a.table_number,
a.game,
a.pair_or_player,
a.score,
21 - b.score
FROM
score AS a,
score AS b
WHERE
a.round = b.round
AND a.table_number = b.table_number
AND a.game = b.game
AND a.pair_or_player != b.pair_or_player
does the trick :-)
Hi I have the following style of table under MS Access: (I didn't make the table and cant change it)
Date_r | Id_Person |Points |Position
25/05/2015 | 120 | 2000 | 1
25/05/2015 | 230 | 1500 | 2
25/05/2015 | 100 | 500 | 3
21/12/2015 | 120 | 2200 | 1
21/12/2015 | 230 | 2000 | 4
21/12/2015 | 100 | 200 | 20
what I am trying to do is to get a list of players (identified by Id_Person) ordered by the points difference between 2 dates.
So for example if I pick date1=25/05/2015 and date2=21/12/2015 I would get:
Id_Person |Points_Diff
230 | 500
120 | 200
100 |-300
I think I need to make something like
SELECT Id_Person , MAX(Points)-MIN(Points)
FROM Table
WHERE date_r = #25/05/2015# or date_r = #21/12/2015#
GROUP BY Id_Person
ORDER BY MAX(Points)-MIN(Points) DESC
But my problem is that i don't really want to order by (MAX(Points)-MIN(Points)) but rather by (points at date2 - points at date1) which can be different because points can decrease with the time.
One method is to use first and last However, this can sometimes produce strange results, so I think that conditional aggregation is best:
SELECT Id_Person,
(MAX(IIF(date_r = #25/05/2015#, Points, 0)) -
MIN(IIF(date_r = #21/05/2015#, Points, 0))
) as PointsDiff
FROM Table
WHERE date_r IN (#25/05/2015#, #21/12/2015#)
GROUP BY Id_Person
ORDER BY (MAX(IIF(date_r = #25/05/2015#, Points, 0)) -
MIN(IIF(date_r = #21/05/2015#, Points, 0))
) DESC;
Because you have two dates, this is more easily written as:
SELECT Id_Person,
SUM(IIF(date_r = #25/05/2015#, Points, -Points)) as PointsDiff
FROM Table
WHERE date_r IN (#25/05/2015#, #21/12/2015#)
GROUP BY Id_Person
ORDER BY SUM(IIF(date_r = #25/05/2015#, Points, -Points)) DESC;
I'm stucking for a solution at the problem of finding daily profits from db (ms access) table. The difference wrt other tips I found online is that I don't have in the table a field "Price" and one "Cost", but a field "Type" which distinguish if it is a revenue "S" or a cost "C"
this is the table "Record"
| Date | Price | Quantity | Type |
-----------------------------------
|01/02 | 20 | 2 | C |
|01/02 | 10 | 1 | S |
|01/02 | 3 | 10 | S |
|01/02 | 5 | 2 | C |
|03/04 | 12 | 3 | C |
|03/03 | 200 | 1 | S |
|03/03 | 120 | 2 | C |
So far I tried different solutions like:
SELECT
(SELECT SUM (RS.Price* RS.Quantity)
FROM Record RS WHERE RS.Type='S' GROUP BY RS.Data
) as totalSales,
(SELECT SUM (RC.Price*RC.Quantity)
FROM Record RC WHERE RC.Type='C' GROUP BY RC.Date
) as totalLosses,
ROUND(totalSales-totaleLosses,2) as NetTotal,
R.Date
FROM RECORD R";
in my mind it could work but obviously it doesn't
and
SELECT RC.Data, ROUND(SUM (RC.Price*RC.QuantitY),2) as DailyLoss
INTO #DailyLosses
FROM Record RC
WHERE RC.Type='C' GROUP BY RC.Date
SELECT RS.Date, ROUND(SUM (RS.Price*RS.Quantity),2) as DailyRevenue
INTO #DailyRevenues
FROM Record RS
WHERE RS.Type='S'GROUP BY RS.Date
SELECT Date, DailyRevenue - DailyLoss as DailyProfit
FROM #DailyLosses dlos, #DailyRevenues drev
WHERE dlos.Date = drev.Date";
My problem beyond the correct syntax is the approach to this kind of problem
You can use grouping and conditional summing. Try this:
SELECT data.Date, data.Income - data.Cost as Profit
FROM (
SELECT Record.Date as Date,
SUM(IIF(Record.Type = 'S', Record.Price * Record.Quantity, 0)) as Income,
SUM(IIF(Record.Type = 'C', Record.Price * Record.Quantity, 0)) as Cost,
FROM Record
GROUP BY Record.Date
) data
In this case you first create a sub-query to get separate fields for Income and Cost, and then your outer query uses subtraction to get actual profit.
I have a simple Parts database which I'd like to use for calculating costs of assemblies, and I need to keep a cost history, so that I can update the costs for parts without the update affecting historic data.
So far I have the info stored in 2 tables:
tblPart:
PartID | PartName
1 | Foo
2 | Bar
3 | Foobar
tblPartCostHistory
PartCostHistoryID | PartID | Revision | Cost
1 | 1 | 1 | £1.00
2 | 1 | 2 | £1.20
3 | 2 | 1 | £3.00
4 | 3 | 1 | £2.20
5 | 3 | 2 | £2.05
What I want to end up with is just the PartID for each part, and the PartCostHistoryID where the revision number is highest, so this:
PartID | PartCostHistoryID
1 | 2
2 | 3
3 | 5
I've had a look at some of the other threads on here and I can't quite get it. I can manage to get the PartID along with the highest Revision number, but if I try to then do anything with the PartCostHistoryID I end up with multiple PartCostHistoryIDs per part.
I'm using MS Access 2007.
Many thanks.
Mihai's (very concise) answer will work assuming that the order of both
[PartCostHistoryID] and
[Revision] for each [PartID]
are always ascending.
A solution that does not rely on that assumption would be
SELECT
tblPartCostHistory.PartID,
tblPartCostHistory.PartCostHistoryID
FROM
tblPartCostHistory
INNER JOIN
(
SELECT
PartID,
MAX(Revision) AS MaxOfRevision
FROM tblPartCostHistory
GROUP BY PartID
) AS max
ON max.PartID = tblPartCostHistory.PartID
AND max.MaxOfRevision = tblPartCostHistory.Revision
SELECT PartID,MAX(PartCostHistoryID) FROM table GROUP BY PartID
Here is query
select PartCostHistoryId, PartId from tblCost
where PartCostHistoryId in
(select PartCostHistoryId from
(select * from tblCost as tbl order by Revision desc) as tbl1
group by PartId
)
Here is SQL Fiddle http://sqlfiddle.com/#!2/19c2d/12